盐碱胁迫对小冰麦种子萌发和早期幼苗生长的影响

Effects of Salt Stress and Alkali Stress on Germination and Growth of Wheat-wheatgrass Earliest Young Seedling

分别将两种中性盐(NaCl和Na2SO4)与两种碱性盐(NaHCO3和Na2CO3)均按摩尔比9∶1混合,在模拟出不同强度的盐碱胁迫条件。比较了盐碱胁迫对小冰麦种子萌发、早期幼苗生长及幼苗中Na+、K+离子含量的影响。结果表明,碱胁迫对小冰麦种子萌发的抑制作用明显大于盐胁迫,而碱胁迫对萌发的抑制可能是致死的。碱胁迫对早期幼苗生长的抑制作用也明显大于盐胁迫,尤其对幼根的抑制作用。碱胁迫明显破坏根的结构和功能,导致根活力急剧下降。盐碱胁迫均造成芽和幼根Na+含量上升而K+含量下降,Na+/K+也随之升高。但若两种胁迫相比,碱胁迫下Na+含量及Na+/K+比值上升幅度和K+含量下降幅度均大于盐胁迫。小冰麦的Na+、K+含量变化特点表明,碱胁迫造成的高pH干扰了根系选择性吸收K+、Na+的能力,而造成了植物体内Na+、K+不均衡,这可能是碱胁迫对小冰麦的伤害作用大于盐胁迫的原因所在。

Seeds and young seedlings of Wheat-wheatgrass were stressed with a range of salt stress （ molar ratio of NaCl： Na2SO4 = 9：1 ） or alkali stress （ molar ratio of NaHC03： Na2CO3 = 9：1 ）. Effects of both stresses on the germination, growth of earliest young seedling,contents of Na^＋ ,K^＋ in young seedling were compared. The results showed that the inhibitory effects of alkali stress on germination and growth of young seedling were much stronger than those of salt stress. Alkali stress especially inhibited the growth of young root, and leaded to the severe reductions in young root activity. In addition, with increasing stress, the contents of Na^＋ and Na^＋/ K^＋ ratio in young seedling increased, while the K^＋ content decreased, and the changes under alkali stress were greater than those under salt stress. This indicated that high pH caused by alkali stress interfered the selective absorption of K^＋ -Na^＋ in roots and resulted in imbalance of intracellular K^＋ -Na^＋, which might be the main reason that the harmful action of alkali-stress on Wheat-wheatgrass was stronger than that of salt-stress.